Even though I am not a fan of polygamy but it is better than hook up culture because of two reasons- identity and honesty.
At least, in polygamy nothing is a secret. At least, people know about those four wives whereas they could have had four secret girlfriends.
Having four wives is better than having four secret girlfriends.
Having four wives is better than having four ex girlfriends.
A husband with four wives is still better than a playboy with ten ex girlfriends.
Many men dump ten girls before settling with one wife.
A man with one wife might have ten ex girlfriends.
If a man has four secret girlfriends or four ex girlfriends, nobody criticises him.
At least, in polygamy, those ladies have some identity and rights.
And much better than ten short term relationships.